Stastaball: Design and Control of a Statically Stable Ball Robot

Abstract

Ballbots are omnidirectional robots in which a robot chassis is built and balanced on top of a ball, thereby allowing for a highly manoeuvrable platform on a planar surface. However, the stability of such robots is performed dynamically with the use of a suitable controller, and thus, power to such robots must be continually maintained. In this paper, a novel approach to the ballbot design is presented in which unpowered static stability is maintained mechanically by a suitable choice of position for the centre of mass of the robot. The simulations of the design and a built prototype evidence the feasibility of such an approach, demonstrating static stability and performance parameters of three degrees of freedom movement, linear speeds of 0.05 m/s, rotation angular speed of 1 rad/s and the ability to traverse inclines up to 3°. Limitations in performance were predominantly due to compressibility of the ball used and power of the motors. Areas for future development to address these issues are suggested.

Keywords

• robotics
• ballbot
• omnidirectional
• Webots
• PID